1) "The researchers conducted a census of major symphony orchestra repertoires. The data collected includes all performances in regular subscription concerts by 27 major symphony orchestras in the United States. "Major" was defined as a symphony whose expenditures exceeded $500,000, as listed in 1972 by the American Symphony League." "The following symphony orchestras were included in the study: Atlanta, Baltimore, Boston, Buffalo, Chicago, Cincinnati, Cleveland, Dallas, Denver, Detroit, Houston, Indianapolis, Kansas City, Los Angeles, Milwaukee, Minneapolis, New Orleans, New York Philharmonic, New York Symphony, Philadelphia, Pittsburgh, Rochester, St. Louis, San Francisco, Seattle, Utah, and the National Symphony Orchestra in Washington DC." Source and further information: http://www.cpanda.org/cpanda/getDDI.xq?studyID=a00225 2) "The Boston Symphony Orchestra, the New York Philharmonic, the San Francisco Symphony, and the Chicago Symphony Orchestra are four of the most influential and important orchestras in the U.S." Source: http://iris.lib.neu.edu/getblob?blobid=8960207030460905 3) "This non-exhaustive list of symphony orchestras in the United States contains American orchestras with entries in the Wikipedia plus other particularly noted orchestras." Source: http://www.answers.com/topic/list-of-symphony-orchestras-in-the-united-states 4) "A player with one of the "big five" orchestras -- Boston, Chicago, Cleveland, Philadelphia and New York -- earns $80,000 and up, so salaries aren't necessarily the issue." Source: http://findarticles.com/p/articles/mi_m1571/is_n42_v13/ai_19986882 5) "The schedule reads like the Who’s Who of the symphonic world.’ Indeed, it does. During the 2004–5 academic year MSM held masterclasses in the art of orchestral performance conducted by principal players from the National, Pittsburgh, Cleveland, San Francisco, Boston, Philadelphia, St Louis, Dallas, Baltimore, Minnesota and New York symphony orchestras" Source: http://www.msmnyc.edu/pdfs/OrchPerf%20-%20Strad%20magazine.pdf